In the construction, farming and logging industries, for example, it is sometimes necessary to build a temporary road over an unstable ground surface, such as that found in swamps or formed of muskeg. Methods such as that shown in U.S. Pat. No. 3,880,538 have been devised for building roads over unstable ground surfaces wherein a mat of rigid polyurethane is laid over the unstable ground surface and then covered with a particulate material or earth fill, the mat acting to distribute the weight of a vehicle traveling over the particulate material and prevent it from sinking into the unstable ground beneath. This method, however, is disadvantageous in that it is expensive in requiring the use of relatively costly plastic materials.
Mats are also used in the construction and mining industries as blasting mats. Here, again, the mats are relatively expensive. In certain cases, for example, the mats are formed from steel cables woven together. A mat of this type is relatively heavy and a crane is required at the construction site to put it in place prior to the blasting operation. Furthermore, inasmuch as the mat is formed from steel, there is always the possibility of a short between the detonation wires.